Myr Retriever + Scrap Trawler + Grinding Station + Mycosynth Golem

Myr Retriever

Scrap Trawler

Grinding Station

Mycosynth Golem

How it works

1. Activate Grinding Station by tapping it and sacrificing Scrap Trawler.
2. When Scrap Trawler dies, it triggers, returning Myr Retriever from your graveyard to your hand.
3. Resolve the Grinding Station ability, causing target player to mill three cards.
4. Cast Myr Retriever by paying 0.
5. When Myr Retriever enters the battlefield, Grinding Station triggers, untapping Grinding Station.
6. Activate Grinding Station by tapping it and sacrificing Myr Retriever.
7. When Myr Retriever dies, it triggers, returning Scrap Trawler from your graveyard to your hand.
8. Resolve the Grinding Station ability, causing target player to mill three cards.
9. Cast Scrap Trawler by paying 0.
10. When Scrap Trawler enters the battlefield, Grinding Station triggers, untapping Grinding Station.
11. Repeat.